Method for producing blower wheels



June 9, 1964 A. D. GOETTL METHOD FOR PRODUCING BLOWER WHEELS 2 Sheets-Sheet 1 Filed Sept. 26, 1960 INVENTOR.

ADAM D. GOETTL way M June 9, 1964 A. D. GOETTL 3,135,035

METHOD FDR PRODUCING BLOWER WHEELS ed Sept. 26, 1960 2 Sheets-Sheet 2 I I I INVENTOR. ADAM D. GO E TTL United States Patent Ofiice 3,136,035 Patented June 9, 1964 3,136,035 METHOD FOR PRODUCING BLOWER WHEELS Adam D. Goettl, Phoenix, Ariz., assignor to McGraw- Edison Company, Milwaukee, Wis., a corporation of Delaware Filed Sept. 26, 1960, Ser. No. 58,526 3 Claims. (Cl. 29-156.8)

This invention relates to a blower wheel construction method and more particularly to a blower wheel construction method whereby blower wheel blades are cast in a flat assembly which comprises streamlined aerodynamic configuration of the blades which are integral with end bars deflectable into arcuate shapes for attachment to annular portions of the blower wheel structures.

The present application is a continuation in part of my copending application Serial No. 851,722 filed November 9, 1959, now abandoned.

In the construction of conventional blower wheels having backwardly curved blades sheet metal has been used to form these blades. The cross section of such blades is generally composed of sheet metal having a uniform thickness from the leading to the trailing edges which are usually square or disposed at right angles to the sides of the blades.

Since air flow through such blower wheels is generally at subsonic velocities it has been recognized that blades of proper aerodynamic shape may contribute to the overall efficiency of such blowers.

Accordingly, it is an object of the invention to provide a blower wheel construction method whereby assemblies of blower wheel blades are cast flat into proper streamlined aerodynamic shapes wherein the blades interconnect a pair of bars which are later deflected into arcuate shapes and coupled to annular portions of a blower wheel structure.

Another object of the invention is to provide a blower wheel construction method whereby blower wheel blades of aerodynamic streamlined shapes may be cast of plastic material in a flat assembly which is readily deflectable into an arcuate assembly and attached to annular portions of a blower wheel structure.

Another object of the invention is to provide a blower wheel construction method whereby aerodynamically shaped blower wheel blades are cast in a flat assembly intermediate integral bars of the assembly which are disposed at opposite ends of the blades; said bars having reduced cross section portions between the blades to permit the assemblies to be deflected into an arcuate shape and to be connected to annular portions of a blower wheel structure.

Another object of the invention is to provide a method for producing a very simple blower wheel construction which incorporates blower wheel blades of proper aerodynamic shape which are very economical to produce and assemble into conventional blower wheels.

Another object of the invention is to provide a method for producing a blower wheel construction wherein assemblies of parallel aerodynamically shaped blades are integral at their opposite ends with a pair of parallel bars; said bars being deflectable into arcuate shape and held in a channel shaped structure which is arcuate and crimped over the bars to hold the blades and bars in assembly with the arcuate channels of the blower wheel.

Further objects and advantages of the invention may be apparent from the following specification, appended claims and accompanying drawings in which:

FIG. 1 is a fragmentary axial sectional view of a blower wheel construction in accordance with the present invention.

FIG. 2 is a fragmentary transverse sectional view taken from the line 2--2 of FIG. 1.

FIG. 3 is a fragmentary sectional view of a plurality of blower wheel blades cast in a flat assembly and showing dies for casting said assembly.

FIG. 4 is a fragmentary sectional view taken from the line 44 of FIG. 3; and

FIG. 5 is a view of a modified blade assembly taken on the same plane as FIG. 3.

As shown in FIG. 1 of the drawings, the blower wheel construction of the present invention is provided with a central shaft 10 having collars 12 and 13 carried thereon. These collars 12 and 13 are provided with peripheral portions 14 and 16 which are disposed in openings 18 and 19, respectively, of blower wheel end members 20 and 22. These end members 20 and 22 are provided with radially disposed spokes 24 and 26, respectively. Integral with the radial spokes 24 and 26 are annular channels 28 and 30, respectively. These annular channels are provided with open sides 32 and 34, respectively, which are directed toward each other and which support bars 36 and 38 of cast blade assemblies as will be hereinafter described.

The cross sectional shape of the bars 36 and 38 may assume a variety of configurations, for example, they may be rectangular as shown or may be circular in cross section as desired. I

Integral with the cast bars 36 and 38 andinterconnecting them are blower blades or impellers 40. Asshown in FIG. 2 of the drawings, the blower blades 40 are conventional aerodynamic forms and are disposed in a backwardly curved direction with respect to the rotational direction of the blower wheel as shown by the arrow A in FIG. 2 of the drawings. These blades 40 are aerodynamically streamlined and have feather edged trailing portions 42 particularly compatible with air moving thereover at subsonic velocities.

The bar 38 shown in FIG. 2 of the drawings is similar to the bar 36 and this bar 38 is provided with reduced cross sectional portions 44 between adjacent blades 40 at their ends so that the bars 36 and 38 of this construction may be cast straight and subsequently deflected into an arcuate configuration to be held in the channels 28 and 30 as will be hereinafter described.

The blade assemblies comprising the blades or impellers 40 and the integral bars 36 and 38 may be cast flat and may be made of any suitable material as desired. Several sections of these blades may be supported in the channels 28 and 30 if desired.

As shown in FIG. 1 of the drawings, it will be seen that alip 46 of the channel 28 is rolled over an inner edge of the bar 36 to retain it in said channel 28, while a like angular portion 48 of the channel 30 is rolled over an inner edge portion of the bar 38 to retain it in the channel 30. It will be seen that edges of the bars 36 and 38 pro ject radially beyond the trailing edges of the blades 40 as shown in FIG. 2 of the drawings to permit the rolled edges 46 and 48 to be formed over the bars 36 and 38 to retain them in the annular channels 28- and 30 of the blower wheel structure. It will be appreciated by those skilled in the art that the areodynamic shape of the blades 40 will improve efliciency of the blower which operates with subsonic air velocities and it will be appreciated that these blades may be accurately cast in proper areodynamic shapes in a flat mold whereupon the bars 36 and 38 due to their reduced cross sectional portions may be deflected into arcuate forms to fit in the annular channels 28 and 30.

The reduced cross sectional portions 44 are formed by opposed curved notches 50 and 52 in the bars between the adjacent blades 40. Thus, the blades are not distorted when the bars are bent since deflection occurs in the reduced bar portions 44 and does not therefore distort or disturb the aerodynamic shape of the blades 40.

As shown in FIGS. 3 and 4 of the drawings, the blower blades 40 and the bars connected at the ends thereof, are cast between dies 55 and 57. These dies 55 and 57 may be provided to cast the blade assemblies of plastic material or any other suitable material as desired. The die 55 is provided with cavity portions 59 which form the convex portions of the blades 40 while the die 57 is provided with portions 61 which form the concave sides of the aerodynamic blade shapes. The dies 55 and 57 are provided with mating faces 63 and 65 disposed between the blades and extending between the leading and trailing edges of the adjacent blades.

As shown in FIG. 4 of the drawings, the end bars 36 and 38 are rectangular in cross section and the die 55 is provided with a channel 67 to form one side of the bars 36 and 38 while the die 57 is provided with an opposed channel 69 to form the opposite portion of the bars 36 and 38.

As shown in FIG. of the drawings the modified bar 36 is provided with opposed notches 70 and 72 which serve the same function as the reduced cross sectional portions 44. Thus, the notches 70 and 72 permit the bars 36 and 38 to be readily deflected into an arcuate configuration.

The method of the invention comprises the casting of impeller members between parallel bars; then deflecting the bars into arcuate configuration then securing them to blower end members carried by a blower shaft.

It will be obvious to those skilled in the art that various modifications of the invention may be resorted to in a manner limited only by a just interpretation of the following claims.

I claim:

1 1. A method for producing blower wheels comprising the casting of a flat assembly of aerodynamically shaped blower blades in parallel relation to each other integral with bars at opposite ends of the blades while currently casting reduced cross-sectional portions in said bars between the ends of said blades, then deflecting said bars, at

said reduced cross-sectional portions, into an assembly having an arcuate disposition and fixing them on annular end members of a blower wheel.

2. A method for producing blower wheels comprising the casting of a flat assembly of aerodynamically shaped blower blades of plastic material in parallel relationship to each other with integral bars at opposite ends of the blades while currently casting reduced cross-sectional portions in said bars between the ends of said blades, then deflecting said bars, at said reduced cross-sectional portions, into an assembly having an arcuate disposition and fixing them on annular metallic end members of a blower wheel.

3. A method for producing blower wheels comprising the casting of a fiat assembly of aerodynamically shaped blower blades of plastic material in parallel relationship to each other with integral bars at opposite ends of the blades while currently casting reduced cross-sectional portions in said bars between the ends of said blades then defleeting said bars, at said reduced cross-sectional portions, into an assembly having an arcuate disposition and fixing them on annular metallic end members of a blower wheel by securing said bars in annular channel portion of said end members.

References Cited in the file of this patent UNITED STATES PATENTS 2,242,586 Marbach May 20, 1941 2,537,805 Wilken Jan. 9, 1951 2,748,462 Hawkinson June 5, 1956 2,937,805 Warnken May 24, 1960 2,991,004 Denbo et al. July 4, 1961 3,041,709 Friedman et al July 3, 1962 FOREIGN PATENTS 21,756 Great Britain 1907 

1. A METHOD FOR PRODUCING BLOWER WHEELS COMPRISING THE CASTING OF A FLAT ASSEMBLY OF AERODYNAMICALLY SHAPED BLOWER BLADES IN PARALLEL RELATION TO EACH OTHER INTEGRAL WITH BARS AT OPPOSITE ENDS OF THE BLADES WHILE CURRENTLY CASTING REDUCED CROSS-SECTIONAL PORTIONS IN SAID BARS BETWEEN THE ENDS OF SAID BLADES, THEN DEFLECTING SAID BARS, AT SAID REDUCED CROSS-SECTIONAL PORTIONS, INTO AN ASSEMBLY HAVING AN ARCUATE DISPOSITION AND FIXING THEM ON ANNULAR END MEMBERS OF A BLOWER WHEEL. 